After two weeks of high political theatre at duelling conventions, the United States presidential race was brought down to earth by a sobering new employment report that highlighted the key weaknesses of both the incumbent and his challenger.

President Barack Obama and the Democrats were generally judged to have had a more successful convention in Charlotte than their Republican rivals did in Tampa.

But any "bounce" that the current occupant of the White House gets in upcoming polls will likely be short-lived, given a weaker-than-expected job report released hours after the Democratic convention ended.

The government's figures showed that just 96,000 new jobs were added last month, well below expectations of around 125,000 jobs. This slow pace of job creation has persisted since April - a trend that will become more damaging closer to the Nov 6 election.

The dire unemployment outlook gives Republican challenger Mitt Romney a golden opportunity to put the lukewarm response he got in Tampa behind him and go on the offensive against Mr Obama.

Mr Romney did not see an appreciable spike in his recent approval ratings, as is common after these feel-good conventions. His keynote speech was, in fact, the most lowly rated since 1996, according to Gallup.

However, the former Massachusetts governor has thus far failed to parlay the widespread economic anxieties of American voters into a significant or sustained lead over Mr Obama. It is unclear whether he will be any more successful this time.

"The basic outline of the election remains unchanged," experts at the University of Virginia's Centre for Politics wrote in an online commentary.

"The President is not in a strong position, but he's not doomed either. While he would love to see better jobs data, he has yet to pay a major political price for it. It is unclear whether he ever will."

Ms Karlyn Bowman, a senior fellow with the conservative American Enterprise Institute, said: "Mr Romney has to continue to hammer away at the economy. It is puzzling that he's been doing a lot of fund-raisers in August, but doesn't seem to be on the campaign trail all that much.

"He can't do that any more. He really needs to get out there and campaign from now until the end of the election."

Unexpected events at home or abroad, say, a meltdown in Europe or a crisis in the Middle East, may yet upend the race. But if the status quo holds, this close election could well come down to two things in the months ahead.

The first is a series of presidential debates next month that would pit Mr Obama against Mr Romney face to face.

After spending hundreds of millions of dollars attacking each other with negative ads, both men would finally get to challenge each other directly on domestic and foreign policies.

Experts are divided on whether these debates make a difference. But Professor Peter Feaver of Duke University argues that the stakes are significantly higher this time round. Both candidates have been running such cautious campaigns that the fallout from any serious mistakes would be significantly amplified, he said.

"These are the last big significant moments when Americans tune in... a disaster in the debates would be harder to recover from," Prof Feaver added.

The second make-or-break factor is the so-called "ground game", something that would be far less visible to the public eye. Given the sharp polarisation of the American electorate, both campaigns believe that there is only a small slice of undecided voters that either side can win over.

Victory then would go to the side that can more successfully turn out the party faithful, particularly in key battleground states like Florida and Ohio. Prior to the conventions in the last two weeks, polls showed Republicans enjoying a significant edge in terms of ground enthusiasm while Democrats were thought to be mostly disillusioned.

But the energy and passion that Democratic activists showed at last week's Charlotte convention prompted many to reassess the extent of this supposed "enthusiasm gap" for Mr Obama. If anything, it was the tepid response given to Mr Romney in Tampa that has now caused many to wonder whether anti-Obama fervour alone would be enough to drive Republicans out in numbers to vote for him.

The Obama campaign appears to be quietly confident on this front, if remarks by Mr David

Plouffe, the architect of Mr Obama's impressive ground operation in the 2008 campaign, are any indication.

"We think that we come out of (Charlotte) with some momentum in terms of putting together the electoral picture," said Mr Plouffe, who is now a senior White House adviser.

"We are not expecting huge movement in this race all the way out to the next 60 days... but there is a chance we might have increased our turnout dynamics."

Mr Jim Messina, the Obama campaign manager, said volunteers have so far made 44 million calls, knocked on 3.8 million doors, and registered more than a million voters. What is more striking, however, is the open display of passion among Obama supporters.

Ms Judy Mount, a Democrat from Florida, broke into tears after she heard Mr Obama's closing speech on Thursday night and said she was more motivated than ever to help canvass votes for the incumbent.

"This convention hyped me up, and I am going back to my county and my state to hype other people up to vote for Mr Obama," she added. "It's all about the energy that flows from person to person."

To be sure, Republican activists who spoke to The Sunday Times in Tampa also said they were fired up and ready to step up their campaign efforts.